1. Field of the Invention
The present invention is related to the field of cargo transport and, more particularly, to an improved side rail and tie plate for transportation vehicles such as trucks, trailers, rail cars and the like.
2. Description of the Related Art
It has long been common practice to transport loads on flatbed vehicles, such as trucks and trailers. These loads are secured to the vehicles using flexible tie-down elements, such as chains, cables and straps. The loads transported by these vehicles often vary widely in shape, size and weight. As a result, many different kinds of apparatus have been developed for tightening and securing tie-down elements to a vehicle deck.
Some trailer manufacturers have incorporated a channel or groove into the floor of the trailer, typically along the outer edge. The channel is generally formed with a flange on either side of the groove opening and usually runs the length of the trailer. The channel is used in conjunction with a tie down anchor. The tie down anchor includes a large end piece, which fits within the channel but is too large to fit past, and thus is retained by, the channel flanges. The body of the tie down anchor extends up through the channel flanges and provides an anchor for a tie down cable, chain or the like.
Since the large end configuration of such a tie down anchor requires that the anchor be inserted into the channel opening at the end of the channel, other configurations have been devised that allow the tie down anchor to be inserted into the channel by passing through the flanges. One such configuration is disclosed in U.S. Pat. No. 6,527,487 to Adams, which includes an anchor hook insertable into a groove or channel formed in the top of the floor of the trailer. While the anchor hook can be inserted through the top of the channel, the total amount of flatbed deck space available for carrying cargo is reduced in the Adams patent configuration.
To address both the need to more easily insert tie down anchors and to overcome the reduction of the deck space problem created by forming channels in the trailer floor, U.S. Pat. No. 6,250,861 to Whitehead discloses a side rail configured to be mounted on the load carrying deck of a transport vehicle. A channel for receiving the tie down anchors is formed in the upper horizontal surface of the side rail, leaving more deck space available.
In each of the foregoing prior art configurations, a channel having two sides, a floor and an open top is formed, either in the top horizontal surface of the trailer floor, or in the top horizontal surface of the side rail. This open-top configuration of an otherwise enclosed channel makes the channel susceptible to becoming filled with loose product, snow, ice, mud or other material that frequently becomes packed into the channel. When this occurs, the channel must first be cleaned out before the associated tie anchors can be inserted therein to subsequently secure the cargo to the vehicle.
Therefore, a need exists for an improved tie down assembly that addresses the foregoing problems.